Flexible hose line, in particular, high pressure hose line which is subjected to a pressurized forming process

ABSTRACT

The invention relates to a flexible hose line, in particular, a high-pressure hose line which is subjected to a pressurized forming process, preferably for variable levels of pressure. Said flexible hose line consists of several layers, at least one of which is configured as a reinforcing layer. The hose line is characterised by an inner layer ( 1 ) with a profile which can be elastically stressed in at least the longitudinal direction of the hose. Said inner layer is the only layer whose length can be modified. The hose line is also characterized by a reinforcing layer ( 3 ) which is configured to absorb the tensile forces acting on the hose in the longitudinal direction, by a compensation zone ( 2 ) which is located between the inner layer ( 1 ) and the reinforcing layer ( 3 ) and which compensates the movement of these two layers in relation to one another and acts as a radial support for the inner layer ( 1 ) on the reinforcing layer ( 3 ); and by connecting areas ( 9 ) for connecting the inner layer ( 1 ) to the reinforcing layer ( 3 ). Said areas are used to define the variable length of the inner layer ( 1 ) as a predetermined utilization length, determined by the length of the reinforcing layer ( 3 ) between the connecting areas ( 9 ).

The invention pertains to a flexible hose line, in particular, ahigh-pressure hose line which is subjected to a pressurized formingprocess, preferably for variable levels of pressure, and a process formanufacturing such hose lines according to the preamble of claims 1 and12.

A flexible hose line for high-pressure media is known from DE 197 28 383A1. This flexible hose line comprises an annular or screw-thread shapedcorrugated metal hose, it is connected to a tubular connecting element,and it has a protective sleeve made of elastic, pliable materialsurrounding the outer sides of the hose line and the connecting element.In the region of the terminal corrugations adjacent to the connectingelement, the protective sleeve features depressions that are directedradially inwards and that engage the valleys of the corrugations of themetal hose.

With such a solution, the transition region between the metal hose andthe connecting element can be designed to accept a load.

The problem of the invention is to develop a hose line that can beexposed to high pressures and, in particular, that can withstandvariable levels of pressure over a comparatively long period.

This problem is solved according to the invention by an inner layer thatfeatures a profile piece that can be elastically stressed at least inthe longitudinal direction of the hose and that is the only layer thatcan be changed in length, by a reinforcing layer that is designed toabsorb tensile forces acting in the longitudinal direction of the hose,by a compensation zone that is arranged between the inner layer and thereinforcing layer and that is used to compensate for relative movementbetween these layers and to support the inner layer in the radialdirection on the reinforcing layer, and by connecting areas between theinner layer and the reinforcing layer, which are used to define thevariable length of the inner layer as a predetermined useful lengthdetermined by the length of the reinforcing layer between the connectingareas.

The invention is associated with the advantage that a hose line with alarge degree of flexibility can be exposed to high levels of pressure,in particular, to variable levels of pressure of large amplitudes. Sucha possibility results from the large flexibility of the inner layerwhich is made less pressure-dependent by the reinforcing layer inconnection with the compensation zone.

The application of pressure leads to shape and position changes of theinner layer that are limited by the reinforcing layer. This producesboth a force acting against the axial expansion of the inner layer andalso simultaneously a reaction force directed radially inwards andtransmitted by the compensation zone. In this way, the compensation zoneis used for the largely uniform reception and distribution of forcesoriginating from the inner layer.

In a preferred embodiment of the invention, the profile piece of theinner layer is designed to be similar to a corrugated tube. The innerlayer can also be a corrugated tube that can change in length for onlysmall material stresses.

In another embodiment of the invention, the inner layer is formed by anelement that can be pretensioned elastically in the axial direction andthat is a component of the hose line in the pretensioned state. Thepretensioning is advantageously chosen such that a certain pretensioningremains even for the largest possible pressure amplitudes in order tokeep material fatigue low even for long use and high pulse-switchingrates.

For special applications, e.g., the use of the hose line for media withan effect on the environment, the inner layer can be designed to have ahigh degree of gas impermeability, which is preferably achieved bymaking the inner layer out of a metallic material.

According to another embodiment of the invention, the reinforcing layeris formed from a mesh, in which the threads of the mesh feature an axialorientation and the preferred mesh angle α, relative to the hoselongitudinal axis, does not exceed 50° and is advantageously within therange of 35° to 45°.

In order to distribute the forces originating from the inner layeruniformly into the support body formed by the inner layer, thecompensation zone, the reinforcing layer, and the connecting areas, thecompensation zone is preferably formed from an elastomer, athermoplastic elastomer, or a thermoplastic. Another favorabledistribution of the forces introduced into the entire system is achievedby sinking the compensation zone into the profile piece of the innerlayer or filling up the profile piece with the compensation zone atleast in the connecting areas.

A method according to the invention for manufacturing a flexible hoseline is realized in that the inner layer and/or the reinforcing layerare provided with a compensation zone bonded to each layer, in that theinner layer and the reinforcing layer are brought into the requiredposition relative to each other through relative movement, and in thatthe inner layers are connected to the reinforcing layer in the region ofthe hose line fittings.

In an advantageous execution of the method, the inner layer ispretensioned in the longitudinal direction of the hose line before theinner layer and the reinforcing layer are connected in the region of thehose fittings.

A force-fit and/or positive-fit connection between the inner layer andthe reinforcing layer can be produced advantageously through radialforces on the component surrounding the reinforcing layer.

The invention is to be explained in more detail in the following withreference to an embodiment and relevant drawings.

Shown are:

FIG. 1, a hose line region, partially in section,

FIG. 2, a hose line section with exposed reinforcing layer, and

FIG. 3, a hose line region with a connecting area between inner layerand reinforcing layer, which has been modified relative to FIG. 1.

The hose illustrated in FIG. 1 at its end region consists of a metallicinner layer 1, an elastomer compensation zone 2, a reinforcing layer 3built as a mesh, and an elastomer outer layer 4.

The corrugated tube-like inner layer 1 is rigidly connected at its hoseend to a connecting piece 5 that features a sawtooth-like contour on itsouter edge and that transitions into a hollow-cylindrical connectingpiece 6. The connecting piece 5 and the region 7 of the inner layer 1adjacent to the connecting piece 5, as well as the radially outwardsadjacent sections of the compensation zone 2, the reinforcing layer 3,and the outer layer 4 are surrounded by a holder 8.

Due to the effects of radial forces, the holder 8 is formed such thatthere is a direct force-fit and/or positive-fit contact between theinner layer 1 and the reinforcing layer 3 on the connecting piece 5,resulting in a connecting area 9 that displaces the compensation zone 2due to the radial forces. In addition, this produces a positive fitbetween the inner layer 1 and the segments 10 of the compensation zone 2engaging the recesses of the profile piece of the inner layer 1.

The mesh of the reinforcing layer 3 is formed from threads or threadgroups 11 that are oriented in the axial direction, as can be seen fromFIG. 2, i.e., they can be loaded in the longitudinal direction of thehose and they run at a mesh angle α of preferably 35° to 45°.

As illustrated in FIG. 3, a support ring 12 can be provided inconnecting area 9, which can set the radial distance of the reinforcinglayer 3 in the connecting area 9. For suitable selection of materials,such a support ring 12 can also increase the positive fit in theconnecting area 9, because the mesh of the reinforcing layer 3 ispressed in the radial direction at least partially into the support ring12 and thus it can be loaded in the axial direction.

For manufacturing the hose line, the corrugated tube-like metallic innerlayer 1 and the composite element (formed from compensation zone 2,reinforcing layer 3, and outer layer 4) are brought into positionrelative to each other, so that the inner layer 1 is surrounded by thecomposite element. In this way, the holders 8 are arranged in theconnecting areas 9 of the inner layer 1 and the reinforcing layer 3,whereby the inner layer 1 is pretensioned in the axial direction and inthe pretensioned state, it is connected and thus fixed to thereinforcing layer 3 through radial, and if necessary also through axial,forces on the holders 8.

What is claimed is:
 1. A flexible hose line, which is subjected to apressurized forming process, comprising: an inner layer having a profilepiece which can be elastically stressed at least in a longitudinaldirection of the hose line, said inner layer can be changed in length, aconnecting piece in communication with the inner layer, a reinforcinglayer that absorbs tensile forces acting in the longitudinal directionof the hose line, a compensation zone arranged between the inner layerand the reinforcing layer, said compensation zone compensates forrelative movement of the inner layer and the reinforcing layer andsupports the inner layer in a radial direction on the reinforcing layer,and a connecting area between the connecting piece and the reinforcinglayer.
 2. Flexible hose line according to claim 1, wherein the profilepiece of the inner layer is designed like a corrugated tube.
 3. Flexiblehose line according to claim 1, wherein the inner layer comprises acorrugated tube.
 4. Flexible hose line according to claim 1, wherein theinner layer comprises an element that can be pretensioned elastically inthe axial direction and that in the pretensioned state is a component ofthe hose line.
 5. Flexible hose line according to claim 1, wherein theinner layer has a high degree of gas impermeability.
 6. Flexible hoseline according to claim 5, wherein the inner layer comprises a metallicmaterial.
 7. Flexible hose line according to claim 1, wherein thereinforcing layer comprises a mesh.
 8. Flexible hose line according toclaim 7, wherein the mesh has threads, said threads feature an axialorientation and a mesh angle α that does not exceed 50° relative to alongitudinal axis of the hose line.
 9. Flexible hose line according toclaim 8, wherein the mesh angle α is within the range of 35° and 45°relative to the longitudinal axis of the hose line.
 10. Flexible hoseline according to claim 1, wherein the compensation zone is formed froman elastomer, a thermoplastic elastomer, or a thermoplastic. 11.Flexible hose line according to claim 1, wherein the compensation zonehas a segment engaging a recess formed by the profile piece of the innerlayer.
 12. Flexible hose line according to claim 1, further comprising:an outer layer in communication with the reinforcing layer.
 13. Flexiblehose line according to claim 12, further comprising: a holdersurrounding the outer layer.
 14. Flexible hose line according to claim1, wherein the compensation zone is in communication with the connectingpiece.
 15. Flexible hose line according to claim 1, further comprising:a support ring in communication with the reinforcing layer.
 16. Flexiblehose line according to claim 1, further comprising: a hollow-cylindricalconnecting piece in communication with the connecting piece. 17.Flexible hose line according to claim 1, wherein the connecting piecehas a sawtooth-like contour.
 18. A flexible hose line, comprising: aninner layer connected at a hose end to a connecting piece, saidconnecting piece having a sawtooth-like contour; a compensation zone incommunication with the inner layer and the connecting piece; areinforcing layer in communication with the compensation zone and theconnecting piece; an outer layer in communication with the reinforcinglayer; a holder surrounding the inner layer, the connecting piece, thecompensation zone, the reinforcing layer, and the outer layer.
 19. Theflexible hose line according to claim 18, wherein the holder is formedsuch that there is a direct force-fit and/or positive-fit contactbetween the inner layer and the reinforcing layer on the connectingpiece.
 20. The flexible hose line according to claim 18, furthercomprising: a hollow-cylindrical connecting piece in communication withthe connecting piece.